Amex/ Marriott Points Usage

I'm planning to cancel my Amex Gold and plarinum this year just because the coupon book feeling hasn't been the greatest. I have ~200k points still. I also have marriott platinum status and ~120k in my marriott account.

I'm planning to travel to China (beijing or shanghai) this summer in July but have generally found horrible points redemption offers for any hotels. I'm planning to use some points on a cathay pacific transfer but a bit lost on how to book all my hotels.

Question is: If I want to use all my Amex points what would be the best value way for me too do so? And when should I use my marriott points? Any marriott hotels in China have ~.5 cents pp so should I just not use them at all?